RIO DE JANEIRO, Sept. 11 (Xinhua) -- The hero of Fluminense's big win over leader Corinthians in the 23rd round of the 2011 Brazilian Championship on Sunday, Fred returned to the locker room and complained of pain in his right thigh.

He is expected to receive a detailed examination on Monday in order to diagnose the problem.

Fluminense's medical staff did not like the news as the injury has been a recurring problem this season. Head coach Abel Braga made the announcement of Fred's injury to the media following his team's impressive 1-0 win over Corinthians.

Braga claimed that Fred will not be able to play in the upcoming classic match-up between Brazil and archrival Argentina on September 14 in the city of Cordoba, Argentina.

The coach speculated that Fred will also miss out on the friendly between the rival on Brazilian soil in the city of Belem on September 28.

Braga fears that the injury will keep Fred sidelined for a lengthy amount of time.

The Fluminense medical staff hopes to administer a magnetic resonance image, an MRI, before Fred is expected to join the rest of the Brazilian national team early on Monday morning when the team travels to Buenos Aires in order to prepare for the upcoming friendly.